Venetian blinds are popular window coverings. This type of blind has a series of slats hung on ladders that extend between a headrail and a bottom rail. The slats can be tilted by moving the rungs of the ladders in opposite directions. Typically, the upper end of each ladder is attached to a drum. The drum for each ladder is on a common axle. Consequently, the slats can be tilted by turning the axle clockwise or counter clockwise. This drum and axle together with any gears that may be coupled to the axle is called the tilt mechanism or tilter.
The tilt mechanism could be operated by a motor but typically is manually controlled. One type of manual control is a cord loop that engages a wheel connected to the axle. A second manual control is a wand that is connected to the axle, typically by a universal joint and one or more gears. Because of child safety concerns, loop drive systems are disfavored. One could substitute two pull cords for the cord loop and some manufacturers have done this. But, a two pull cord system is more expensive and difficult to make than a cord loop. Of even more concern is that users tend to mistake the pull cords that operate the tilter for the lift cords that raise and lower the blinds. No such confusion occurs when a rod or wand is used to operate the tilter.
To operate a tilter using a wand, the operator must grasp the wand and rotate the wand about is longitudinal axis. Some people, particularly people who have arthritis in their hands, have difficulty grasping and rotating a rod. The art has developed a variety of wands which can be rotated by moving an outer sleeve up and down a central rod whose upper end is attached to the tilt mechanism. The central rod is threaded. Those threads engage threads on the inside of the sleeve. Consequently, movement of the sleeve along the rod will cause the rod to rotate. Examples of this type of tilt wand can be found in U.S. Pat. Nos. 6,089,303 and 6,298,897. One problem with this type of wand is that the sleeve must be moved up and down several times to move the slats from a closed position to an open position and from an open position to a closed position.
Some vertical venetian blinds have a single control which rotates the vanes and moves the vanes across the headrail. Commonly, this type of control has a cord loop. Pulling one side of the cord loop of an extended open blind with vanes perpendicular to the window initially rotates the vanes while continued pulling causes the vanes to move along the headrail. Pulling the opposite side of the loop initially rotates the vanes in an opposite direction. Continued pulling will move the vanes along the headrail in an opposite direction. This same action can be achieved in a horizontal blind using a control system in which the drums for the ladders and the spools on which lift cords are wound are all on a single axle. That axle is then operated by a cord loop as in the vertical blind. A wand or crank could be substituted for the cord loop. Because many rotations of the wand or crank are needed to raise the blind, a crank is much easier to operate than a wand.
Consequently, there is a need for an operating wand for a venetian blind tilt mechanism, or for a combination tilt and lift cord control device which is easy to operate by any user, even if the person has arthritis in his or her hand.